


All Bite

by addressingstars



Category: Kingdom Hearts
Genre: Alpha/Beta/Omega Dynamics, Biting, Dom/sub Undertones, Established Relationship, M/M, Muzzles, Scent Marking
Language: English
Status: Completed
Published: 2020-02-15
Updated: 2020-02-15
Packaged: 2021-02-28 07:42:34
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 5,750
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22730101
Author URL: https://archiveofourown.org/users/addressingstars/pseuds/addressingstars
Summary: Yes, he bit Xemnas. A lot. Especially in the intense throes of his heat. But Xemnas never brought it up so Saïx was convinced that they had mutually decided to ignore it.Explicit a/b/o with lots of extra words thrown in.
Relationships: Saïx/Xemnas (Kingdom Hearts)
Comments: 4
Kudos: 82





	All Bite

"...What is that?" Saïx asked sharply, frowning at the nondescript box in Xemnas’s hands.

He was seated primly on the edge of Xemnas’s desk, one leg crossed over the other in his usual fashion. They were in Xemnas’s private quarters, a typical late-morning meeting place for the two of them. The other members of the castle had all been sent away on missions by Saïx himself.

"Something for you," Xemnas said cryptically, his tone offering no hints. He was dressed down in a black sleeveless undershirt tucked into his uniform trousers. Only Saïx ever got to see him in such a casual setting.

Xemnas padded barefoot over to Saïx and pressed the box into his hands.

"Open it," he said, and planted a chaste kiss on the top of Saïx's head.

Saïx shuddered. This close, Xemnas smelled _good_. As his alpha and mate, Xemnas always smelled good to Saïx—however, his scent was at its best when Xemnas dropped his airs in the comfort of his own den. Saïx turned his eyes down and away from Xemnas’s expectant gaze and carefully pried the lid off the box.

He wasn't quite sure what he was looking at. Sitting at the bottom of the box were inconspicuous black leather bindings attached to what appeared to be a metal cage. The whole thing was about the size of two fists.

"...What is this?" Saïx dared to ask.

"Something I thought could be useful," came the easy reply. Xemnas leaned over and plucked the mystery item out of the box to dangle it in between them. Saïx glanced between his hands and his exposed forearms. Tanned, muscular, and absolutely _covered_ in dark bite marks in various stages of healing.

"It's…" Saïx recoiled slightly as the pieces clicked together in his mind. "I don't think—"

He didn't find it very funny. Saïx felt an indignant warmth rise to his cheeks, but Xemnas’s expression meant he was being serious.

Saïx wanted to crawl inside his own skin to escape the reality of the situation. Yes, he bit Xemnas. A lot. Especially in the intense throes of his heat. But Xemnas never brought it up so Saïx was convinced that they had mutually decided to ignore it.

Yet here Xemnas was, muzzle in hand, smiling down at him.

It was difficult enough for Saïx to come to terms with being collared by this man. But the idea of being _muzzled_ as well reached a whole new depth of depravity.

"Do you like it?" Xemnas asked teasingly. When Saïx's only answer was a noncommittal grunt, Xemnas leaned in so his chin was resting on his lieutenant's shoulder. His lips barely brushed the shell of Saïx's ear.

"There's no need to pout," he hummed, dark and low. "I know you can't help yourself, but I would much prefer it if you would bite only when I expressly permit it."

Saïx still didn't say anything, but he could feel his body growing as hot as his face.

It was nearly noon. He had work to do. Xemnas may have been his alpha, but that didn't mean he was going to roll over and resign himself to the life of a docile, mated omega—one who did nothing all day but await their master’s next call.

Saïx tried to pull away from the tangle of Xemnas’s long silver bangs and alluring scent, but found that he was caught quite firmly.

Xemnas didn't seem to notice his omega's restlessness—or at least didn't pay any mind. The enigma of Nobody seemed content with piddling the day away with his omega and his games. Games that only he knew the rules to.

It was as if all urgency in advancing the Organization's nebulous agenda had been set aside and forgotten after he had claimed and mated Saïx. He seemed content with spending his waking moments teasing and doting on his omega—a behavior which split Saïx down the middle.

Saïx's normal, heartless, _non_ -pheromone-addled side wanted to use this lull in Organization activity to gain leverage and scheme in defiance of Xemnas’s leadership. If Xemnas wasn't going to get them their hearts, then he damn well would try to do it himself.

Unfortunately, his omegan side—the one that was so desperately attracted to his boss that he went ahead and mated the bastard—reveled in Xemnas’s attention even if it was just on a superficial level. As Nobodies, their connection shouldn't have been more than physical...and yet, somehow, Xemnas was able to push and prod Saïx to get him to do exactly what he wanted.

Usually against Saïx's better judgement.

Xemnas could satisfy his omegan side so _thoroughly_ that his animal mind often attempted to trick him into thinking he had a heart again.

"Shh," Xemnas soothed, jolting Saïx's mind back to the present. Sometimes Saïx's brooding was so loud that it was probably audible beyond the bone of his skull.

"Rest your worries," Xemnas patted the top of Saïx's head. "I know you work yourself up over these things."

Saïx grumbled, but the hand on his hair did feel good.

"Let's just focus on the present, yes? Your reports can wait."

...And that was final. Saïx's shoulders slumped as he resigned himself to his fate. Xemnas was right—and he certainly had a way of quieting the anxiety that bubbled up beneath his skin.

"Would you like to try it on?" Xemnas suddenly asked, picking up the muzzle.

Saïx grumbled. No, he didn't want to try it on, much less wear the humiliating thing. He already felt like an animal even when he wasn't being actively restrained like one.

"Now, don't give me that look," Xemnas tutted, sounding more fond than scolding. He tugged at Saïx's sleeve to get him to dismount the desk and walked him a few feet away towards the center of the room.

Saïx couldn't help but follow, entranced as always by his alpha.

Xemnas seemed almost unreal at times. Simultaneously glowing with phantasmic beauty whilst maintaining the domineering build and presence of the most well-respected alphas.

His features and physique, cut from warm amber, could have only been forged in a place out of reach of normal, mortal men. The silvery stands of his hair glowed around his head like a halo, and fell across his broad shoulders like a veil of stars.

Xemnas was smiling warmly at him, and, in truth, it unnerved Saïx. Those kinds of looks were reserved for _humans_ with _feelings_ , not whatever facsimile they were. But Xemnas still kept up the act—even when they were alone. The pheromones must have been driving Xemnas’s actions just as strongly as they controlled a beguiled Saïx.

Saïx, on the other hand, was unorthodox for an omega. In fact, it was a surprise that he presented as one at all. While shorter than his mate, he was just as proportionately muscled, spending hours and hours every day exhaustingly honing both his combat and magic skills. Xemnas had allowed him to keep training and working even after becoming his alpha. Which Saïx supposed made them both a little unconventional in respect to their biological roles.

Instead of looking typically ‘omegan’, Saïx instead had sharp features and a mean face, made worse by the angry red X that split it down the middle. His bright blue hair stuck out everywhere, despite his best efforts to tame it. Xemnas always told him he was beautiful and perfect, but Saïx avoided mirrors, lest he catch a glimpse of the monster that he had become. He envied the easy confidence that an alpha like Xemnas always seemed to exude.

Although, someone like Xemnas had nothing to be insecure about.

Saïx was startled from his haze by the warm press of lips against his own. Xemnas had stooped down to kiss him, and brought a finger to the point of his chin. Saïx obediently tilted his head up, allowing Xemnas to kiss him deeper.

He hummed into his alphas mouth, each nip and nibble lighting him up and sending sparks down his spine. But Xemnas broke away too soon, and Saïx found himself blinking rapidly— momentarily disoriented—as the grounding presence of his alpha was pulled away from him.

Xemnas had taken a step back to openly appraise the entirety of his omega. It made Saïx want to curl in on himself.

"Saïx, kneel," Xemnas ordered, all natural authority.

While one part of Saïx's mind did not want to kneel and would prefer to keep kissing, his animal brain went ahead and sent the electrical signals to the backs of his knees before he could manually override it. He lowered himself onto the floor fluidly; boots tucked neatly beneath him and palms flat against his leather-clad thighs.

He kept his eyes straight forward. Looking at Xemnas would look like supplication…and he still had the presence of mind to stop himself from sinking _that_ low.

Ever since Saïx presented as an omega, his life had become a nonstop battle between rational behavior and a millennia of bred-in instincts. Sometimes, Saïx was almost _thankful_ that he had no heart. He wasn't sure if he could handle the emotional strife that would undoubtedly plague him if he had to deal with something as base as _feelings_. He glared at Xemnas’s legs.

Xemnas made a noise of affirmation. "Good," he purred, and Saïx couldn't help but be warmed by the praise. Xemnas reached down and brushed some errant strands of Saïx's hair behind his ears...or at least that's what Saïx thought he was doing. It turned out that Xemnas was actually gathering his hair and sweeping it to the side so he could secure the leather straps of the muzzle behind Saïx's head.

Saïx grimaced as the cold metal frame was placed on his face over his nose and mouth and fastened shut. Not tight enough to pinch, but certainly tight enough to make removing it impossible without the use of both hands. The use of which he was sure he was going to be denied very shortly.

"Chin up," Xemnas said sharply, tapping the side of the muzzle. Saïx tilted his head up but still refused to meet Xemnas’s eyes. His face was burning up in what _might_ have been shame and humiliation—if he was able to feel those things. Saïx didn't need emotions to understand the position he was in: muzzled like a dog. Less than a person, less than a Nobody.

Xemnas held him by the jaw and tilted his head side to side to inspect his handiwork. "Ah, I'm glad it fits, I wasn't completely sure..." he muttered, more to himself than Saïx. His lips relaxed into a smile.

"It suits you," he proclaimed, "though I believe you don't need any help looking fierce on your own..." a pause, then, "would you like your collar too?"

Saïx shook his head more vehemently than he intended. Already the muzzle made him FEEL more feral. He wanted to bite Xemnas’s fingers just to prove he could. He didn't want his collar; he wasn't ready to give up his last shred of autonomy.

Saïx was, in a sense, thankful that Xemnas only made him wear his collar when they were alone. More often than not, domineering alphas would make their omega mates wear their collar all the time—as if their overpowering scent alone wasn’t enough to announce to the world ownership of their omega.

Everyone knew he belonged to Xemnas. Though even before Saïx was mated the other members knew better than to make a pass at him. They might lose a finger, after all.

"If that’s what you would like," Xemnas conceded to his non-answer, and Saïx was relieved to find no trace of disappointment in his alpha's voice.

"Come, Saïx, I would like to re-scent you before turning you back out to the wilds," Xemnas chuckled a bit and held out his hand for his kneeling omega.

Saïx grasped Xemnas’s hand and pulled himself up on shaky legs. He let himself be led to the large daybed that sat to the side of the room beneath a floor-length window. He could see his own menacing reflection growing larger in the inky black of the glass—his face muzzled and scowling. He wanted to hide.

Thankfully, Xemnas turned him around and seated him on the edge of the bed. There were no windows or mirrors on this side of the room, yet Saïx still saw his reflection in the shadow of a man before him. Eyes locked: gold on gold, amber on amber.

Xemnas was the one to break eye contact first, leaning in to unclasp the chain intersecting the collar of his jacket. He opened the zipper next, and Saïx scooted slightly to help him finish removing the rest of his long coat. 

Saïx could feel the cold air rush towards his skin and settle into his bones as soon as he was deprived of his protective layer. Saïx saw Xemnas’s face twitch minutely as he was hit by Saïx's undamped scent.

An unscripted pause from Xemnas was good. It meant Saïx could still catch him off guard.

Xemnas folded his coat neatly and placed it on an undisturbed corner of the bed, which Saïx appreciated—especially since Xemnas had no problem turning him back out to the castle as soon as he finished "scenting him". Which was his term for literally rubbing his scent all over Saïx. By means of direct contact.

While this was not an entirely unusual thing for mated couples to do, it was certainly old-fashioned. But Saïx needed his coat left intact—he didn't want the other members to make assumptions about what he did in the castle all day (although it was probably far too late for that).

Xemnas ran his hands over Saïx's pale neck and shoulders, stopping to caress the skin just outside the steel cage on his face. Saïx reached out to touch Xemnas’s waist, but stopped just a hair’s width away, waiting for permission.

Xemnas smiled and took his Saïx's hands in his own and placed them on his body. He was warm under the thin, straining fabric of his shirt.

Saïx untucked Xemnas’s undershirt while Xemnas ran his hands down his arms, pausing on occasion to inspect a cut or bruise. Looking to see if any marks weren't from _him_. He took Saïx's hands again and pulled off his gloves—but not before turning them over to examine the ring of bruises Saïx sported on both wrists.

Satisfied, Xemnas hummed in approval before letting Saïx's continue.

Saïx worked to remove Xemnas’s belt while the latter went back to touching his face. Fingers began to trace the branches of his x-shaped scar, and he jerked away, just slightly. He tried to disguise his flinch as a movement to slide Xemnas’s belt off, but he knew Xemnas wouldn't have missed his reaction.

Xemnas didn't say anything but he didn't try to touch the scar again.

Saïx struggled with the front of Xemnas’s pants. The zipper was pulled tight across the growing bulge of his cock and he could feel the heat of it, even through the heavy fabric. Saïx’s hands were shaking and Xemnas was watching him, his hands in Saïx’s hair.

He freed Xemnas’s cock and helped divest him of the rest of his clothes, leaving them in a pool on the floor. He was hit by a wave of pheromones coming from Xemnas's freshly exposed skin. The strength came not so much from scent (although he did have one, and he smelled rich and smokey with a hint of musk)—so much as Saïx's own body's reaction to being this close to his naked alpha.

He was already feeling flushed, and all that heat suddenly became tenfold and settled deep in the pit of his stomach. The sight and proximity of his mate's cock made his own dick stir and he felt the distinct throb of his body readying itself to be mated. Saïx squeezed his thighs together, the seam of his pants digging painfully into his trapped dick while simultaneously providing a satisfying pressure to the rest of his arousal.

"Saïx, be still," Xemnas commanded his squirming omega. He crouched in front of Saïx, thigh muscles bulging, and helped him remove his boots and pants. Saïx was fully nude now, and a deep blush was blooming all the way from his face down to his erection; throbbing and pink and nestled in a bed of soft blue hair.

Saïx felt the acute need to shield himself and protect his modesty, but he knew it would displease his alpha—so he turned off the conscious part of his mind and let instinct take over, stretching out and spreading his legs to allow Xemnas to inspect him in full.

“You're beautiful," Xemnas said after a few moments, and the sincerity in his voice warmed Saïx's cheeks. He had almost forgotten about the muzzle as Xemnas gently laid him back and crawled over his body, his long silver hair tickling his overly sensitive skin.

Of course, Saïx was rudely reminded of the muzzle restraining him when Xemnas stopped at his shoulders; practically sitting on his chest and boxing him in with his knees. Saïx's eyes almost began to water at the intense closeness to Xemnas’s most potent scent, and he blinked up at his alpha, trying to convey his desperation without words or sound.

Xemnas bumped his very interested cock up against the metal of Saïx's muzzle and Saïx whined at the near contact. So much for no sound. He was becoming more and more frenzied with each passing moment. The muscles of his arms twitched but he knew better than to touch Xemnas without permission. So he sat in agonizing stillness as Xemnas continued to rock his hips up against the metal cage, forcing Saïx to take him in with sight and scent alone. Saïx panted and snarled. He felt so depraved, acting this starved for his alpha's dick.

Saïx growled to express his frustration and Xemnas only responded by tapping the side of his cheek with the flushed tip of his dick. It left a sticky pool of precome and Xemnas smeared it across his face and neck.

"Beautiful," Xemnas said again—although in Saïx's mind the words 'filthy' and 'debauched' seemed more appropriate given his current position.

Saïx watched with hooded eyes as Xemnas dragged his leaking cock down the length of his body, across his rapidly rising and falling chest and his taut stomach.

Xemnas paused rub his dick against Saïx’s, and Saïx gasped at the agonizingly pleasurable touch. Xemnas’s penis was thick and dark, much like the man himself, and it contrasted nicely with the angry pink and reds of his own dick. Xemnas stroked both of them, smearing his precum up both their lengths.

"Good boy," he said, giving Saïx's dick one last squeeze and appraising look before pulling away. An omega's penis was unusual in that it served no reproductive purpose—just sexual pleasure. It was generally smaller than an alpha's and couldn't knot, but still oozed a thin, clear fluid—as Saïx's was now.

Xemnas was sufficiently satisfied with his work and gave Saïx a quick kiss on the muzzle before grabbing him by the hips and flipping him over onto his stomach. Saïx yelped in surprise and Xemnas chuckled fondly, a sound that seemed to come from deep within the inky void where his heart should have been.

χ

Xemnas let his eyes wander over Saïx's moonlit form, his pale skin practically glowing against the dark bed sheets. Flipping him over had made a mess of his beryl-blue hair, the strands sticking all over to the fragrant sweat on his face and body. It exposed the dark mating mark on Saïx's neck, and Xemnas felt a wave of possessiveness ripple through him.

It was just a physical response to his mate lying naked before him, he insisted to himself.

Truth be told, there were times when Xemnas could not tell where his pheromone-driven actions ended, and the memory-driven ones began. Bonding as an alpha was not something that existed in either of his predecessors' histories. This endeavor was new territory for him, and he wandered untethered in the dark—his body's insatiable attraction to Saïx his only beacon.

The decision to make Saïx his mate was a logical one (Xemnas told himself), that would cement the omega to him physically, if not entirely mentally. Xemnas didn't let his adoration blind him. They were still Nobodies.

And now, as mates, Saïx's scent had synchronized with his own, calling to him like a siren's song. A pale lure bobbing in an endless black sea.

Saïx was mostly still besides the slight twisting motion of his thighs as he ground them together, trying and failing to relieve his mounting arousal. Saïx was not currently in his heat cycle, but his body still responded beautifully to his alpha—getting ready practically all on its own.

"Ughhh...Xemnas…" Saïx whined, trying to spur his alpha into action. And Xemnas certainly wasn't going to deny his omega—or himself—any longer.

He got behind Saïx and pulled his hips towards him, not being gentle at all. He pressed the head of his cock directly against Saïx's slick-soaked hole, the contact feeling so good and _right_ that he had to bite his lip to stop from groaning out loud. Saïx's flesh burned like a hot molten core and he smelled so good that Xemnas was certain that it could warp the mind of even the most stoic of alphas.

Saïx didn't bother to stifle his sounds, moaning openly at the intimate contact. His muzzle forced his head down at an awkward angle against the bed, and he twisted himself further to watch Xemnas with his wild, golden eyes.

He was pushing back against him now, trying and failing to spear himself on his alpha’s cock. Xemnas’s dick was too large to fit without applied force on his part, but he let him struggle with it anyway.

His omega was always so impatient. _"Let me get back to work"_ , _"hurry up and put it in"_ , and of course: _"how much longer until we get our hearts back?"._

Sometimes he wished he could reveal to him the entire truth. Xemnas had set the board long ago, and now began the agonizing wait for all the pieces to fall into place. If only Saïx could see the bigger picture as he did...then perhaps he could confide in him the true scope of his plans.

However, for the time being, he had to be content with only being able to share this—their superficial physical connection. Their bodies may have been bonded together, but the rest was just playing at being mates.

Xemnas sat his omega up on his knees and Saïx glared at him desperately over one flushed shoulder. He started with Saïx's neck—sweeping his hair to the side to press open mouthed kisses to the sensitive skin on his nape. This seemed to calm Saïx a bit. Xemnas ghosted his lips over the mating mark he had placed so many cycles ago; the skin had long since healed into a set of shiny pink crescents, but his teeth were still a perfect match. Xemnas knew he would never again reach the insurmountable physical pleasure of placing a permanent claim on his chosen omega.

Saïx must have also been thinking of the same moment, because he grew still as Xemnas traced his teeth over the mark. Perhaps, like this, an alpha and omega became very close to knowing each other’s minds. A biological impossibility—but Xemnas couldn't deny that he felt closest to his omega when they were together like this.

Xemnas didn't break the skin again. He knew it would displease Saïx to bear a new, visible mark when he worked so closely with the rest of the Organization. So he compromised and sucked a deep purple bruise below his shoulder. Saïx moaned.

"Nnng, Xemnas, please. I want this off," Saïx hissed, tugging at the leather straps on his muzzle.

Xemnas covered him more fully with his body and said, “Shush, if you complain again I might get you a gag instead. Would you prefer that?”

Saïx shook his head, tossing hair into Xemnas’s face. But he obeyed and didn't say anything further. Xemnas pried one of his hands off the muzzle and pinned it behind his back, then used his free hand to cup the cage over his mouth, holding Saïx’s head steady. When Saïx stopped squirming he resumed kissing down the length of his spine.

Although Saïx stopped talking, he still moaned and whined and gasped as Xemnas scented him. He never expressly forbade those kinds of noises, and Saïx knew that if Xemnas was going to force him to be patient, it was only fair to test his alpha's resolve as well.

χ

“Aaahhhnnn…” Saïx groaned, shameless, as Xemnas’s mouth reached just below his tailbone. Xemnas pressed a hand insistently against Saïx's back, forcing him even lower against the bed and his ass higher in the air. Saïx strained his neck to try and look back at his alpha, but Xemnas's head had dipped out of sight. Saïx should have expected the sudden shock and subsequent tremors of pleasure as Xemnas placed his burning hot mouth over Saïx's hole. But it surprised him nonetheless, and he yelped and jerked forward.

Xemnas smacked his ass hard enough to sting as punishment for flinching. This made Saïx cry out, but he kept still. Xemnas continued to lick and suck on the soft ring of muscle that circled his asshole. Saïx could feel his slick flowing freely and mixing Xemnas’s pheromone-charged saliva.

Saïx nearly had a panic attack the first time Xemnas ate him out. He _would’ve_ had one if Nobodies were capable of such a thing. It was not something he ever thought was done by an alpha to their omega. It seemed so wrong to have his alpha buried between his legs and freely licking at his slick and sweat. It should have disgusted him—but the sensation was so, so good. A million nerve endings he didn't know he had were lit up in ways that he would never have known through penetration alone. And Xemnas seemed to enjoy it, if his satisfied hum and persistent erection were anything to go by.

Saïx scrunched his eyes shut as Xemnas continued to tease and lick him. He wasn’t able to clamp a hand over his mouth with the muzzle in the way, so he attempted to bury his face into the bed sheets instead. He bit at his lips but couldn't help but cry out when Xemnas penetrated him with his tongue.

Xemnas seemed content with torturing him like that, with just his tongue, and hummed low and deep, causing Saïx's whole body to shudder. Saïx was clawing desperately at his hair and the sheets. It wasn't enough. Every inch of his hormone-addled body was screaming for his alpha to finally fuck him.

" _Xemnas..._ " he growled.

“What did I say...?” Xemnas scolded, a thin line of fluid trailing off his lips as he pulled himself up. Saïx noticed with a twinge of pride that Xemnas was beginning to sound flustered himself. He supposed sticking one's face in the center of their omega’s arousal would do that to an alpha.

Saïx didn't relent even after Xemnas's warning. He gnashed his sharp teeth together within the confines of their cage and pleaded with his alpha to hurry up and fuck him.

Xemnas scolded him again, but contrary to his sharp words, he repositioned himself behind Saïx so his hips were level with Saïx's upturned ass. But ever the tormentor, he contented himself with rubbing against Saïx's overstimulated hole, smearing viscous precum all over Saïx's ass.

That had a potent scent that would stick to Saïx's skin for hours. And Xemnas knew it, too. When he was in a particularly possessive mood he would order Saïx to his knees and slowly feed him his cock, only to send his omega back to work moments just after filling his throat with his cum. If any of the other Nobodies smelled it on Saïx, they were smart enough not to say anything.

Saïx was becoming _very_ frustrated now. His body was wound up like a spring—a tension that could only be relieved by his alpha. To his relief, Xemnas eventually conceded, and draped his hard, muscled body over Saïx's hunched-over form. He mouthed at Saïx's neck, and Saïx could smell his own slick all over his lover's face. Saïx's neglected cock throbbed from where it stood firm between his legs.

Xemnas made soothing noises and planted his arms on each side of Saïx's head, lining his dick up with Saïx's hole. Saïx thought he was going to cry in relief as he felt the very tip of Xemnas’s cock push past the first ring of muscle.

It wasn't painless. Even if they fucked every day— _multiple times a day_ —Xemnas was still significantly larger than Saïx and his dick was always a tight fit. But Saïx savored it, and the pain was insignificant compared to the intense, intense feeling of finally getting fully filled by his alpha. The physical sensation was so great it almost seemed to seep into the realm of emotion—and that, to Saïx, was what made it all worth it.

Xemnas was going slow. There were other times when their coupling was more violent—where Saïx sought to inflict as much pain upon his alpha as Xemnas did to him. But now wasn’t one of those times. As Xemnas pushed into him again, he felt himself struggling against the inextricable weight and pressure of the body on top of his. He thrashed beneath Xemnas and bumped his muzzle against Xemnas’s scarred arms. This was when Saïx usually started biting. He couldn't help himself. The pain and pressure could only be soothed by sinking his fangs deep into flesh. He struggled without that crutch as Xemnas speared him further on his cock.

Xemnas petted his hair and murmured, " _good boy_ ," as Saïx gnashed his teeth together. He growled at his alpha and tried to pull away out of defiance, but Xemnas held him fast. It was only when Xemnas was fully seated that he let out a groan unbidden. Saïx took in mouthfuls of air as his innards shifted to accommodate the intrusion.

Xemnas only gave him moments to adjust before he drew back and started thrusting in earnest. Saïx moaned openly as every sensitive spot inside of him was pressed all at once. His own cock throbbed, impossibly hard, as Xemnas began to fuck him fully.

Saïx was crying out at full volume. A more cognant version of himself might be worried that a straggler in the castle might overhear them, but he was too caught up in the painful pleasure to care. He clawed hands found their way to Xemnas’s forearms, tense with strain, and tried to sink into his skin; determined to mark him where he was unable to with his teeth. Xemnas quickly pinned those, too, and Saïx felt himself falling apart without a mouthful of flesh to ground him.

Unable to focus on anything but the relentless cock fucking into his body, Saïx came quickly and without warning. A hot white brand clouded his vision and his whole body seized up and relaxed, waves of pleasure washing over his entire self—from head to toe and to the deep depths of where his heart _should have_ been. It was almost too much.

χ

Xemnas hummed in approval as he moved a hand from his now-pliant omega’s wrists and onto the jut of his hip for better leverage. His thrusts became erratic as Saïxs body instinctively contracted around his dick in attempts to milk him of his cum. It was working, too, and Xemnas felt his knot start to swell at the base of his cock. He slowed down, just barely, because the sudden increase in pressure could be very painful for Saïx—who had meanwhile returned to weakly trying to bite his arms.

Saïx wasn't on his heat cycle so they wouldn’t tie, that didn’t stop Xemnas from dumping inordinate amounts of cum into his omega’s ass as orgasm overtook him. He fell forward, just slightly—his sweat-soaked chest pressing against Saïx's equally sweaty back—and panted hard. It was a rare display of outwards vulnerability, but Xemnas couldn’t find it within himself to care.

He slid out of Saïx when his knot had gone down and his cock had finished emptying itself. Saïx shuddered at the sudden loss of pressure. Xemnas rolled Saïx's pliant and fucked-out body over onto his back, and stretched himself out on the bed beside him.

Saïx was watching him with glazed over, adoring eyes. They were as striking as they were eerily familiar in their bright gold. But he blinked and the moment was over, and Saïx's expression melted into one much more stoic as he returned to his senses.

“Take it off,” Saïx demanded, not bothering to mind his tone. Xemnas sighed and obliged, reaching behind Saïxs head to untangle his hair and remove the bindings.

The muzzle slid off and Saïx was left with a faint red indent around his mouth and nose from where the metal had dug into his skin. But before Xemnas could do so much as pull his hands back, Saïx lunged forward and bit him fully on the fleshy part between his neck and shoulder.

Xemnas yelped in uncharacteristic surprise, and Saïx’s laugh was muffled by a mouthful of flesh. When he pulled away his lips and pointed teeth were stained with blood. That was going to leave a scar.

 _‘What an animal’_ , Xemnas thought—but a reprimand was the last thing on his mind as Saïx leaned in for a bloody kiss. _‘I love him.’_

No, not love. Never love, just a fondness for physicality, he corrected himself.

And, in the end, he knew that this connection would be burnt to ashes and scattered to the wind, as if it had never existed. He shifted to allow Saïx to rest his head against his chest. Saïx’s earlier agitation seemed to have dissipated, at least for the moment.

Xemnas took this opportunity to tug him closer. He would savor what they had.

While it lasted.

χ

**Author's Note:**

> Thanks for reading! I rushed to get this out on valentine's day, so please let me know what you think and if there's any glaring mistakes.
> 
> HMU https://twitter.com/Torrentia_FP


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